Massive haemorrhage and transfusion

Abstract

Massive blood loss is defined as the loss of one blood volume within 24 hours. Normal blood volume is 70 ml/kg in adults (ideal body weight), 60 ml/kg in the elderly and 80–90 ml/kg in children. An alternative definition of massive blood loss is the loss of 50% of the blood volume within three hours or a rate of loss of greater than 150 ml per minute.¹

In adults, several definitions of massive transfusion (MT) exist based on the volume of the blood products transfused and also the time frames over which these transfusions occur. The three most common definitions of MT in adult patients are (i) transfusion of ≥ 10 red blood cell (RBC) units, which approximates the total blood volume (TBV) of an average adult patient, within 24 hours, (ii) transfusion of > four RBC units in one hour with anticipation of continued need for blood product support, and (iii) replacement of > 50% of the TBV by blood products within three hours.²